System and method capable of simultaneous radiographic examination and radioactive material inspection

Abstract

The present invention relates to the field of radiographic examination and radioactive material inspection, and provides a system and a method capable of simultaneous radiographic examination and radioactive material inspection. The system comprises a radiographic examination system and a radiation monitor; wherein the radiographic examination system comprises an accelerator and a synchronization controller, and the radiation monitor comprises a detector, a front end circuit, a signal transmission controller, a data collecting, analyzing and processing computer, an alarm device and so on. The present invention combines the radiographic examination system and the radiation monitor tightly so that the radioactive material inspection can be executed while the radiographic examination is performed, thereby the examination efficiency is improved and the occupied area of the system is reduced.

1. A system capable of simultaneous radiographic examination and radioactive material inspection, comprising a radiographic examination system and a radiation monitor; wherein the radiographic examination system comprises an accelerator and a synchronization controller, and the radiation monitor comprises a detector, a front end circuit, a signal transmission controller, a data collecting, analyzing and processing computer and an alarm device; and wherein a synchronization controlling signal coming from the synchronization controller in the radiographic examination system forms a gate signal with adjustable pulse width in the signal transmission controller in the radiation monitor, which is used to remove the data collected by the radiation monitor during the emission of the accelerator. 
   
   
     2. The system as set forth in  claim 1 , wherein the radiation monitor sets an alarm threshold on the basis of a background count rate. 
   
   
     3. The system as set forth in  2 , wherein a modified PMT additional circuit is provided in the radiation monitor to achieve rapid recovery of the detector after short-time high-dose irradiations. 
   
   
     4. The system as set forth in  claim 3 , wherein the system cuts down the source of the electrons by controlling electric field between the first dynodes of the PMT by means of an external synchronization signal to effectively remove the affect of the short-time high-dose X/γ radiations. 
   
   
     5. The system as set forth in  claim 3 , wherein the PMT adopted in the photomultiplier tube additional circuit is provided with a voltage divider loop having a cathode grounded or a voltage divider loop having an anode grounded. 
   
   
     6. A method capable of simultaneous radiographic examination and radioactive material inspection, comprising the steps of:
 initializing and self-checking at a radiation monitors; 
 entering into a background mode to detect radiations, and continuously collect and timely update the background count rate, and generate an alarm if the intensity of the background radiation goes beyond the normal range; 
 triggering an occupancy/speed sensor, and causing the monitor enter into a detection mode if a vehicle with containers comes into the detection area of the monitor; 
 emitting X/γ radiations from an accelerator by pulses to start radiographic examination for the containers; 
 cutting down the source of the electrons generated by the PMT by controlling electric field between the first dynodes of the PMT using an accelerator emission synchronization signal from a radiographic examination system, to effectively remove the affect of the short-time high-dose X/γ radiations; 
 completing the radiographic examination and radioactive material inspection after the vehicle has passed through the inspection passage. 
 
   
   
     7. The method as set forth in  claim 6 , wherein if the radiation monitor needs system maintenance, it enters into a maintenance mode from the background mode, in which advanced functions are executed. 
   
   
     8. The method as set forth in  claim 6  or  7 , wherein in the step of cutting down the source of the electrons, the accelerator emission synchronization signal is sent to the radiation monitor through the synchronization controller, and forms a gate signal with adjusted pulse width in the signal transmission controller in the radiation monitor to remove the data collected by the monitor during the emission of the accelerator. 
   
   
     9. The method as set forth in  claim 8 , wherein a modified PMT additional circuit is provided in the radiation monitor to achieve rapid recovery of the detector after short-time high-dose irradiations. 
   
   
     10. The method as set forth in  claim 9 , wherein the PMT adopted in the photomultiplier tube additional circuit is provided with a voltage divider loop having a cathode grounded or a voltage divider loop having an anode grounded. 
   
   
     11. The method as set forth in  claim 8 , wherein the radiation monitor sets an alarm threshold on the basis of the background count rate when the monitor detects no objects.